End-of-hold notification (EOHN) schemes have been proposed to allow one party to a phone call (referred to herein as “Party A”) to suspend the phone call and receive a signal when the other party (referred to herein as “Party B”) is available to continue the phone call. For example, Party A might want to activate EOHN if Party B puts Party A on hold, switches over to another phone call, steps away from the phone, or otherwise disengages from the conversation. Among other things, EOHN allows Party A to avoid continually aurally monitoring the line and to be notified when the call can be resumed.
Generally speaking, EOHN works as follows. Party A activates EOHN, e.g., by pressing a designated key or entering a designated code on his or her phone. A message is played to Party B to inform Party B that EOHN has been activated and perhaps telling Party B to press a key (or a specific key) to reconnect with Party B. When a determination is made that Party B is ready to reconnect (e.g., upon detecting a key pressed by Party B), a signal is sent to Party A's phone to inform Party A. A signal also may be sent to Party B's phone to let Party B know that Party A is being contacted.
In various EOHN schemes, the message played to Party B's phone may be played by Party A's phone, by the phone system, or by other devices in communication with Party B's phone. Similarly, detecting when Party B becomes available may be performed in a variety of ways (e.g., detecting that the call has been removed from hold, detecting a key pressed by Party B, etc.) and by any of various devices. Also, the signal sent to Party A's phone may be any of a variety of signals, including an actual call back to Party A's phone, a digital signal that causes Party A's phone to ring and/or vibrate, etc. Depending on how these various features are implemented in a given EOHN system, Party A might or might not hang up after activating EOHN; the phone call between Party A and Party B might or might not be disconnected; and devices that perform EOHN functions might or might not require specific hardware.
In addition to the core EOHN functionality as discussed above, additional signals may be sent to Party B's phone to control an indicator (e.g., a light), which may be turned on when Party A activates EOHN and turned off if and when Party A deactivates EOHN (which may be done before Party B even knows that EOHN had been activated). For example, special DTMF tones may be played at the beginning of each iteration of the message, with special detection circuitry used to detect the signals and control the indicator.
The following U.S. patents may be relevant to EOHN systems: U.S. Pat. Nos. 3,961,142; 4,731,822; 5,155,761; 5,185,782; 5,436,967; 6,141,328; 6,885,741; 6,031,905; 4,425,479; 4,834,551; 5,764,746; 5,822,403; 5,875,231; 6,885,741; 6,597,779; 6,400,804; 6,768,722; 6,219,415; 6,118,861; 6,301,346; 6,704,565; and 6,597,779.
The following relate to on-hold systems that employ speech recognition to detect “off-hold” condition:
U.S. Pat. No. 6,122,346 (Grossman) mentions speech recognition.
US Publication No. 2007/0003045 says that a hold determination system may use automatic speech recognition logic to determine that a party has taken the first call off hold and begun speaking. The speech recognition logic is able to distinguish active voice from a recording or music typically used by call centers. Active voice is defined herein as speech from a person being a party to a call, as distinguished from recordings or music.
US Publication No. 2009/0207996 (Berger) relates to something referred to as an Independent Communication System (ICS) that is used to wait on hold and provide a notification upon detecting voice cues indicating that the live operator is available.
PCT Publication No. WO 2010/028327 (Kole) relates to an on hold call back telephone feature.
Each of the references mentioned above is hereby incorporated herein by reference in its entirety.